Humans may have company when it comes to midlife crises

Do middle-aged chimps get the urge to buy an expensive European roadster?

Midlife crises strike millions of people each year, throwing them into depression, making them question their success, and prompting them to buy ridiculously expensive cars. Sociologists have proposed many possible causes of the ubiquitous midlife crisis, ranging from feelings of regret to financial hardship and unmet expectations. However, new evidence from a somewhat unlikely place—zoos and primate sanctuaries—suggests that midlife crises may have more to do with our evolutionary history than previously thought.

Since we share so much with our great ape relatives, researchers wondered if they, too, tended to have decreased well-being in the middle of their lives. The researchers recruited more than 500 captive great apes, including chimpanzees and orangutans, from North America, Australia, and Asia, to take part in the study. Caretakers, primate researchers, and volunteers that were familiar with the apes were asked several questions, such as whether the individual was in a positive or negative mood and how much pleasure they currently derive from various situations. These responses were averaged and used to determine the general happiness and well-being of each ape.

Just as in humans, well-being in the apes was U-shaped, declining steadily until reaching a low point, then increasing until death. On average, apes were rated as least happy at 31.9 years old, which is approximately middle age for an ape. Like humans, chimpanzees and orangutans appear to experience a type of psychological “crisis” in the middle of their lives, in which their well-being is at its lowest point.

The similarity suggests that there may be an evolutionary aspect to the midlife crisis. The researchers suggest (but didn't test) a few possible mechanisms for low well-being during middle age in both apes and humans. First, brain changes across our development may cause the U-shaped well-being graph in humans and their closest ape relatives. Alternatively, our ability to deal with our feelings—and possibly our regrets—may change as we age, with both our emotions and our coping mechanisms reaching low points in the middle of our lives. Finally, it’s also possible that happiness and longevity are related, and that unhappy primates may die off at higher rates than others, especially later in life.

The authors of the study recognize that social and cultural causes likely play a role in midlife crises in humans, and rightly state that these factors should continue to be investigated. But the results of the study, published in PNAS, certainly suggest that something in our shared history with great apes predisposes us to a low point in middle age.

Questionnaires such as the ones used here have been met with some criticism, but in recent years, research has shown that subjective assessments of animals can be reliable and representative if conducted under specific conditions. In this case, the questionnaires were filled out by multiple people who knew the animals well and interacted with them regularly for at least two years. Inter-rater reliability was high, indicating that different observers tended to respond similarly when talking about individual great apes.

While there are shortcomings and limitations to the study, it appears that cross-species research may play a role in helping us understand how and why happiness and well-being change as we age. Further research on great apes and other animals may help us understand why our 40s and 50s are difficult for so many people, and may hint at new ways to cope with this tumultuous time in our lives.

Is it just me or is the art of significant digits on the decline? 31.9 years of age seems awfully precise to me Granted, it's quoted as an average, but it's the precision of the number I question. By extension, if a chimp was born in January of 2000, he will most likely have his low point in life around October/November of 2031? I'm not dinging the author per se, as I'm fairly certain the number was quoted somewhere else, but it does illustrate the importance of the correct usage of significant digits.

Edit: I will admit that the only reason I brought this up is that I had a conversation with one of my kids about this the other day.

I feel like I am going through a midlife crisis now that I am in my thirties. Can person go through it earlier than 40? After all midlife is just half your life gone. Not everyone lives to the ripe old age of 88. Some people drop dead in their 60s or 70s. If this isn't a midlife crisis I hate to think what it will be like because I am very miserable and regretful now and I haven't even reached 40 yet!

I don't get why people are surprised to learn other apes share our quirks. We share the same hierarchical social structure. We are more like the other apes than many would like to admit. Only three things separate us from them. Our intelligence, our ability to think beyond the present, and our masterful ability to make and use tools.

Is it just me or is the art of significant digits on the decline? 31.9 years of age seems awfully precise to me Granted, it's quoted as an average, but it's the precision of the number I question. By extension, if a chimp was born in January of 2000, he will most likely have his low point in life around October/November of 2031? I'm not dinging the author per se, as I'm fairly certain the number was quoted somewhere else, but it does illustrate the importance of the correct usage of significant digits.

Edit: I will admit that the only reason I brought this up is that I had a conversation with one of my kids about this the other day.

It's just an arithmetic mean. Would you feel better if they said 32 years instead? It seems arbitrary in this context, but it's appropriate to include this level of significance in a scientific study if the original data contained this level of significance -- of course, that's a debate in itself, and not covered here... I could not speculate on how exactly they determine the age of the primates, unless they were born in captivity.

I don't get why people are surprised to learn other apes share our quirks. We share the same hierarchical social structure. We are more like the other apes than many would like to admit. Only three things separate us from them. Our intelligence, our ability to think beyond the present, and our masterful ability to make and use tools.

Some days, I have serious doubts about your first two criteria when it comes to humans.

I'm in my mid-twenties, and I'm going through the 40-55 category... both good and bad happened, but the bad that's happened has thrown a curve ball of uncertainty in my life. Then I bought an expensive sports car.

Is it just me or is the mid-life crisis spawning a similar younger brother, the quarter-life crisis? I seriously feel like I'm in stuck in the "life's a b*tch" rut.

Is it just me or is the art of significant digits on the decline? 31.9 years of age seems awfully precise to me Granted, it's quoted as an average, but it's the precision of the number I question. By extension, if a chimp was born in January of 2000, he will most likely have his low point in life around October/November of 2031? I'm not dinging the author per se, as I'm fairly certain the number was quoted somewhere else, but it does illustrate the importance of the correct usage of significant digits.

Edit: I will admit that the only reason I brought this up is that I had a conversation with one of my kids about this the other day.

It's just an arithmetic mean. Would you feel better if they said 32 years instead? It seems arbitrary in this context, but it's appropriate to include this level of significance in a scientific study if the original data contained this level of significance -- of course, that's a debate in itself, and not covered here... I could not speculate on how exactly they determine the age of the primates, unless they were born in captivity.

I suspect you're missing the point. Not criticizing, mind you, but my point was the number stated in the article, how it relates to significant digits, and why it is suspect. I wouldn't 'feel better' if the number stated was 32, but 32 would more than likely be a much more correct number for 31.9 indicates far more precision than what was probably gleaned from the study.

In other words, in a study of 500 great apes they calculated an average of 31.9 years. If you are versed in mathematics, engineering, science, etc. you would know that the statement of 31.9 years implies that they knew the low point of a great apes life to within 3 significant digits, or in another way of stating it, they knew each and every low point of all 500 plus ape's lives within a 10th of a year. My contention with this is the number quoted is most likely a statistical impossibility. It seems quite wrong to state as accurate the formentioned number with that amount of precision.

I'm in my mid-twenties, and I'm going through the 40-55 category... both good and bad happened, but the bad that's happened has thrown a curve ball of uncertainty in my life. Then I bought an expensive sports car.

Is it just me or is the mid-life crisis spawning a similar younger brother, the quarter-life crisis? I seriously feel like I'm in stuck in the "life's a b*tch" rut.

I think I have the most likely explanation. This is a side effect of two processes: first, our memory prioritizes the negative over the positive; second, our memory starts failing at some point. Because of the former, even if negative/regrettable experiences are a small fraction of positive and neutral ones, they can come to dominate the picture of our lives looking back. Once memory begins to fade, though, the less frequently relived memories will tend to disappear first, allowing our picture to start unskewing.

I feel like I am going through a midlife crisis now that I am in my thirties. Can person go through it earlier than 40? After all midlife is just half your life gone. Not everyone lives to the ripe old age of 88. Some people drop dead in their 60s or 70s. If this isn't a midlife crisis I hate to think what it will be like because I am very miserable and regretful now and I haven't even reached 40 yet!

I think entrance into a midlife crisis isn't so much about chronology as maturity. Some people mature at a very young age due to hardship or great love. They'll have their "midlife" crisis at tender age. Others can avoid the crisis altogether due to wealth, denial, or whatever. These become the elderly folks that aren't Elders (or Crones).

I believe the entry criteria for a midlife crisis is a critical failing in our "script for life". We find out that what we were taught, or what we believed, doesn't stand in the face of a growing body of contrary life experience. We need a new script, but have no idea what that is. Most folks double-down on the old script to try to make it work. Maybe a new sports car! Or a new spouse! But if the script has genuinely failed, these efforts eventually will too.

The bottom of the U is when we're in between scripts and have no effing clue. It's a brutal place. It akin to a caterpillar becoming a butterfly. The caterpillar "knew" who it was: it knew how it moved, how it slept, what it looked like, how it ate, etc. Now it's a pile of goo, not a caterpillar anymore but not yet a butterfly. It doesn't know what the hell is happening, other than something bigger than its awareness is setting its path. It cannot see the end like we can. And yes, it will move different, it'll sleep different, it'll look different, etc. Its fears of "drastic change" are genuine.

CG Jung calls this process Individuation. Bill Plotkin estimates that 20% of Americans start through it, but only 10% make it out. This is pretty shitty because this is critical stuff for us as a people. The current manifestations of our religious traditions are generally failing us, as is culture.

Bottom line, Sapphire2012, keep up the good work!!!! Find a friend for the journey who will encourage you to continue on rather than bail.

Is it just me or is the art of significant digits on the decline? 31.9 years of age seems awfully precise to me Granted, it's quoted as an average, but it's the precision of the number I question. By extension, if a chimp was born in January of 2000, he will most likely have his low point in life around October/November of 2031? I'm not dinging the author per se, as I'm fairly certain the number was quoted somewhere else, but it does illustrate the importance of the correct usage of significant digits.

Edit: I will admit that the only reason I brought this up is that I had a conversation with one of my kids about this the other day.

It's just an arithmetic mean. Would you feel better if they said 32 years instead? It seems arbitrary in this context, but it's appropriate to include this level of significance in a scientific study if the original data contained this level of significance -- of course, that's a debate in itself, and not covered here... I could not speculate on how exactly they determine the age of the primates, unless they were born in captivity.

I suspect you're missing the point. Not criticizing, mind you, but my point was the number stated in the article, how it relates to significant digits, and why it is suspect. I wouldn't 'feel better' if the number stated was 32, but 32 would more than likely be a much more correct number for 31.9 indicates far more precision than what was probably gleaned from the study.

In other words, in a study of 500 great apes they calculated an average of 31.9 years. If you are versed in mathematics, engineering, science, etc. you would know that the statement of 31.9 years implies that they knew the low point of a great apes life to within 3 significant digits, or in another way of stating it, they knew each and every low point of all 500 plus ape's lives within a 10th of a year. My contention with this is the number quoted is most likely a statistical impossibility. It seems quite wrong to state as accurate the forementioned number with that amount of precision.

I don't really disagree, but that's what happens when you try to apply math to behavioral psychology...

And remember, 0,1 year is pretty close to one month, so I don't find it surprising that the assessors, who were familiar with the primates they were studying, would be able to effectively determine which ones seemed the happiest and least happy over time. Then, it's pretty simple to factor in the age of the primates and do some basic math to draw some curves that one can hang a hypothesis upon.

I don't get why people are surprised to learn other apes share our quirks. We share the same hierarchical social structure. We are more like the other apes than many would like to admit. Only three things separate us from them. Our intelligence, our ability to think beyond the present, and our masterful ability to make and use tools.

Apes have shown to be able to think beyond the present. We do tend to produce and use more advanced tools than Apes do and depending on who you ask, not all people are smarter than Apes.

Just saying.

I'd say what really seperates us from the great Apes is a propensity toward wearing clothing.

You nailed it, though perhaps the year count differs for each of us. I think my "40-55" was a little shorter (fewer years) but more terse and to the point. (Maybe a chemical-induced influence.) Now I'm bowling! Gitter done. (I'm planning to live forever. So far, so good.)

My "midlife crisis" came in the form of a nervous breakdown 12 years ago, brought about by crazy, slave-driver bosses and seven years without a vacation in the go-go tech sector. I wonder how many more such "midlife crises" are nothing more than long-term fatigue, resulting in anxiety and/or depression to a greater or lesser degree. In my own experience, getting past the crisis and recovering involved letting go and learning to take life, employers and crazy bosses less seriously, not by going out and buying an expensive roadster. At any rate, I seriously doubt that middle-age chimps entertain thoughts of buying roadsters, expensive or otherwise.

I don't get why people are surprised to learn other apes share our quirks. We share the same hierarchical social structure. We are more like the other apes than many would like to admit. Only three things separate us from them. Our intelligence, our ability to think beyond the present, and our masterful ability to make and use tools.

Some days, I have serious doubts about your first two criteria when it comes to humans.

I don't get why people are surprised to learn other apes share our quirks. We share the same hierarchical social structure. We are more like the other apes than many would like to admit. Only three things separate us from them. Our intelligence, our ability to think beyond the present, and our masterful ability to make and use tools.

In my opinion, the only thing that separates humans from other apes or animals is the ability to effectively pass and aggregate knowledge to others and younger generations. Early humans didn't have particularly more advanced tool-making ability than some other animals, it seems.

As for the topic, I wonder how this study could be done to the wild apes. Do we tag sensors to them and monitor the signals? Human observers can't keep an eye on them as effectively as the captive ones.

As someone aged around 40 who is significantly less happy recently than two years ago although having a significantly better professional position than a couple of years ago, I started to pay attention to studies on mid-life crisis as I suspect I am currently facing it. It's an interesting read that apparently apes undergo midlife crisis as we humans do with the underlying presumption that it is somehow a heritage of evolution.I would have argued that midlife crisis is strongly connected to culture and society and would like to see some studies on midlife crisis among different countries and cultures.

If it turns out that it is kind of a "force of nature", maybe it would let me feel slightly better :-)But then any excuse is ok if it lets us avoid to mature ...

The bottom of the U is when we're in between scripts and have no effing clue. It's a brutal place. It akin to a caterpillar becoming a butterfly. The caterpillar "knew" who it was: it knew how it moved, how it slept, what it looked like, how it ate, etc. Now it's a pile of goo, not a caterpillar anymore but not yet a butterfly. It doesn't know what the hell is happening, other than something bigger than its awareness is setting its path. It cannot see the end like we can. And yes, it will move different, it'll sleep different, it'll look different, etc. Its fears of "drastic change" are genuine.

CG Jung calls this process Individuation. Bill Plotkin estimates that 20% of Americans start through it, but only 10% make it out. This is pretty shitty because this is critical stuff for us as a people. The current manifestations of our religious traditions are generally failing us, as is culture.

This is expounded on at a more individual level by Joseph Campbell and Robert Bly, among others. Apparently it's an ancient observation put out in legend and lore that we are recently coming full circle again to understand. I seem to remember Bly calling it "ash work", comparing it to the "cinder-biters" of Scandinavian culture-- of course, the symbolism of the Phoenix descending and rising from the ashes applies, too.

I just wanted to comment and say this is a very refreshing article to find on Ars. I am turning 30 and not handling it well. For some reason I couldn't figure out why. I was depressed, felt as if my last 30 years was a complete waste. My wife has had such trouble finding work in this economy and we both have been unable to progress on our plans to start a family. I did the absolutely dumb thing and bought a very expensive truck...i had no idea why either.

This article really planted a seed that maybe I am going through a midlife crisis and I need to seek some professional therapy. I mean its almost perfectly scripted.

So thank you for bringing this issue to my attention. I enjoy the work you guys do.

Kate Shaw Yoshida / Kate is a science writer for Ars Technica. She recently earned a dual Ph.D. in Zoology and Ecology, Evolutionary Biology and Behavior from Michigan State University, studying the social behavior of wild spotted hyenas.